Which set is not equal to A = {1, 2, 3}?
Answer and explanation
Correct answer: {1, 2, 3, 4}
Sets are equal when they have exactly the same distinct elements; the order does not matter, and repeated elements are counted only once. Thus options A and D contain the same elements as A, while option B also represents {1, 2, 3} because 1 is repeated. Option C has the additional element 4, so it is not equal.
Frequently asked questions
What is the correct answer to this question?
{1, 2, 3, 4}
Why is this the correct answer?
Sets are equal when they have exactly the same distinct elements; the order does not matter, and repeated elements are counted only once. Thus options A and D contain the same elements as A, while option B also represents {1, 2, 3} because 1 is repeated. Option C has the additional element 4, so it is not equal.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: The Empty Set, Finite and Infinite Sets, Equal Sets.
